How's this for a photo opportunity? Andrew Mitchell, the international development secretary, is perched on the side of a truck talking to female police officers in Somaliland.

Unlike many photo-ops, this is no gimmick. Mitchell this week became the first British cabinet minister to visit Somaliland with a serious purpose in mind – to show how he is redirecting Britain's overseas budget to countries in genuine need. Aid to Somalia is to be trebled from £26m in 2010/11 to £80m in 2013/14.

Mitchell occupies an enviable position in the cabinet. His budget was only one of two to be ring-fenced by the Tories in their general election manifesto. The other was the health budget.

The international development secretary knows this brings huge responsibilities to show he is spending wisely. Mitchell told the Guardian in July that he is under a duty ensure money is being well spent in light of his "privileged position" of having a ring-fenced budget. David Cameron has pledged to meet the UN target of spending 0.7% of Gross National Income (GNI) on overseas aid by 2013.

Soon after taking office in May Mitchell showed his intent when he announced bilateral reviews of all 102 countries supported by Britain. Some richer countries, such as China and Russia, will lose support as aid is directed towards the needy.

And this week we saw where some of that money will go when Mitchell stopped by for his chat with police in Somaliland, a self-declared sovereign state which Britain only recognises as an autonomous region of Somalia. During his visit to the capital, Hargeisahe, he met President Silanyo of Somaliland and toured a hospital.

Ever the diplomat, Mitchell chose his words with care as he announced that British aid to Somalia would be tripled:

British aid to Somalia is helping to save lives. This week I met a three-year old girl who had been on the verge of starvation. Now she is on the way to recovery, thanks to the kind of emergency nutrition that Britain will provide for some 40,000 starving women and children.

As a member of Britain's new national security council, Mitchell said the aid would also benefit Britain:

This is not just aid from Britain; it is aid for Britain too. Our aid to Somalia is helping to make Britain safer, because conflict doesn't just claim innocent lives in Somalia, it also leads to international problems like piracy, migration and terrorism. None of these will be solved without tackling their root causes: ongoing instability and extreme poverty.

Mitchell believes the aid will provide the following help:

• Emergency nutrition for more than 40,000 starving women and children.• Safe drinking water to 350,000 people.• Access to basic, life-saving healthcare for 268,000 people.• Help for 68,000 people to keep their animals alive. This is a vital lifeline for families during droughts.

Mitchell was given a less than friendly welcome back to Britain by Harriet Harman, his Labour shadow, who raised questions about the Tories' commitment to meeting the 2013 UN spending target. In a speech today at the LSE, Labour's deputy leader announced a 'Keep the 0.7% / 2013 Promise' campaign because of what she called the Tories' "fragile" commitment to the target.

Harman pointed out that legislation to enshrine the commitment, promised in the Queen's Speech, has still not appeared. A senior DfID source told the Guardian last night of Harman's attack:

This is a pretty weak attack given that the coalition has promised to do it in the first session of this parliament which ends in June 2012.

We are also the first country in the G20 to set out the financial pathway to the 0.7% commitment. If that is the best Harriet Harman can do we will put that down as a tick for the coalition's development policy.

The usually uncontentious area of overseas aid may soon become a little more heated.